Cross-flow cooling tower apparatus with single or multiple air entry passages, and chambers for heat/mass transfer media, which are frequently cooling towers with fluid transfer medium, having gravity-fed fluid flowing through to be cooled by transversely flowing air. These present apparatus have fluid systems and circuits including pumps to provide fluid at a pressure at the upper end of the cooling towers. The fluids at a pressure have both a static and dynamic component with the static pressure being relatively small for a conduit connection directly extending from the pump to the upper end of the tower for deposition of warm fluid in a fluid basin at an elevated dynamic pressure. Transfer of fluids with a large dynamic component is associated with high turbulence, and these fluids are more difficult to control during fluid distribution to the basin pans and the fluid transfer media. Erratic fluid flow to the fluid transfer media results in erratic flow through the fluid transfer media and concomitantly inefficient fluid cooling. A discussion of the differences between static pressure and the dynamic or velocity head (pressure) is provided in Cameron Hydraulic Data, edited by G. V. Shaw and A. W. Loomis, Twelfth Edition, Third Printing, Ingersoll-Rand Company, New York, N.Y. (pp. 9-13).
In an attempt to control the fluid turbulence and to more smoothly deliver fluid at an elevated temperature for cooling in the transfer media, flow control valves are provided in the fluid circuit to receive the warmed fluid at a dynamic pressure, abate the turbulence and provide smooth, even distribution of the warmed fluid to the basin pan or pans for transfer to the fluid-cooling media. A flow control valve is illustrated in U.S. Pat. No. 4,592,878 to Scrivnor which incorporates a rotary flow control valve and a predistribution pan in cooperation with a distribution pan. This valve is positioned above the transfer media of a tower to receive the warm fluid flow. However, as with most tower assemblies the location of operating assemblies in remote or relatively inaccessible regions requires framing, ladders, catwalks and other associated structural members for viewing, repair or replacement. The flow-control valve and structural assemblies are all added cost factors, which components are required as a result of the distribution problem associated with the relatively large dynamic component of fluid pressure at the upper end of the tower and the associated turbulence and irregular fluid distribution. The requirement for a flow-control valve is especially evident when it is necessary to balance the flow to two (2) or more distribution basin pans.
Cross-flow cooling towers, as illustrated in the above-noted U.S. Pat. No. 4,592,878 to Scrivnor and more particularly in U.S. Pat. No. 2,732,190 to L. T. Mart, are utilized to reduce the temperature of a fluid (water) by a current of air horizontally traversing a cooling tower media having the fluid coursing vertically downward. Fluid is communicated to the basin above the towers from a supply source, for downward flow through the fluid cooling media, which may be horizontal slats, molded panels, or other media. The cross-flowing air and any air-entrained fluid flows through a drift eliminator section, which captures most of the entrained water particles, prior to air discharge from the tower. The warm fluid received from a piping network may carry spalled sidewall rust or other particulate material in the fluid stream. The entrained particulate material can lead to clogging of apertures in the basin, which would require maintenance at the tower upper end at the basin pan to dislodge and remove the entrapped materials, and to clear the orifices for unimpeded fluid transfer.
As a consequence of all of the above it is desirable to remove entrained particulate matter from fluids transferred to the cooling towers before fluid transfer to the basin pan or pans. Further, obviating the need for a flow-control valve would reduce the assembly size, avoid maintenance of the valve above the tower and remove the necessity for ladders, catwalks and support structures for accessing the additional equipment. A flow-control valve is generally required above each basin pan of a cross-flow cooling tower system, and in the position above the towers these valves are relatively difficult to service and maintain. Therefore, any provision to eliminate or alleviate these valves would avoid not only the original equipment cost, but also avoids the maintenance and service costs, as well as lost cooling capacity time during periods of poor fluid distribution.